Case study:River Fugla

From RESTORE
Jump to: navigation, search
0.00
(0 votes)


To discuss or comment on this case study, please use the discussion page.


Location: 63° 26' 38", 10° 54' 56"
Edit location
Loading map...
Left click to look around in the map, and use the wheel of your mouse to zoom in and out.


Project overview

Edit project overview
Status Complete
Project web site
Themes Habitat and biodiversity, Monitoring
Country Norway
Main contact forename Arne Jørgen
Main contact surname Kjøsnes
Main contact user ID User:Kasvio
Contact organisation NVE (Norwegian Water Resources and Energy Directorate)
Contact organisation web site http://www.niva.no
Partner organisations
Parent multi-site project
This is a parent project
encompassing the following
projects
No
Rocks, gravel and roots were placed to the brook (photo Arne Jørgen Kjøsnes)

Project summary

Edit project overview to modify the project summary.


The river Fugla is a small river in Hell in Stjoerdal community in the middle part of Norway. River is situated next to the river Stjørdalselva. This is in an area susceptible to slides and the river has been cutting increasingly deeper into the potential unstable sediments.

Quick clay is a type of marine clay prone to sudden loss of strength when disturbed. After failure the clay may become liquid, and this could lead to big landslides. Primarily found in the upper region of the Northern Hemisphere. Quick clay slides occur without warning and may wipe out large areas often causing loss of life and substantial material damage. Landslides can be triggered by high rivers that erode and saturate clay slopes, by melt water and rain that destabilize a deposit or by human activity such as fillings, excavations etc.. In populated areas with high risk of landslide hazard, improvements as raising the river bottom is used to stop erosion. In many rivers and brooks large stretches of the river bed might be raised by several meters and both the river bed and banks will be plastered with erosion-proof rocks.

NVE secured this river for further erosion and the work was conducted with the use of erosion-proof rocks both in the river bed and banks for a total distance of about 600 meters. Prior to the mitigating work the water quality was poor and the river was often colored grey due to erosion. Also logs, roots etc were placed in the brook and spawning gravel in to the rapid areas.

The construction work protects the area from the slides. At the same time it can ruin habitats for anadromous fish and aquatic invertebrates. To restore the river and recreate suitable habitats for sea trout and salmon, some simple mitigating measures were done. Building small weirs to create deeper ponds, adding spawning gravel, roots with rootwad, and the use of logs and large woody debris, made the river more suitable for aquatic organisms. Mitigating measures were set up over a distance of about 250 meters of the river. With the measures done the river now lookes more natural.

Monitoring surveys and results

Edit project overview to modify the Monitoring survey and results.


The brook is now more suited for fish because the water quality is better. One month after the restoration work numerous sea trout individuals were observed spawning in the River Fugla.

Lessons learnt

This case study hasn’t got any lessons learnt, you can add some by editing the project overview.


Image gallery


River Fugla 2.JPG
River Fugla 3.JPG
ShowHideAdditionalImage.png


Catchment and subcatchment



Site

Name
WFD water body codes 124-44-R
WFD (national) typology
WFD water body name
Pre-project morphology Artificial channel, coloured water due to erosion
Reference morphology Straightened
Desired post project morphology
Heavily modified water body Yes
National/international site designation
Local/regional site designations
Protected species present No
Invasive species present No
Species of interest Brown trout (Salmo trutta), Atlantic salmon (Salmo salar)
Dominant hydrology
Dominant substrate Clay
River corridor land use
Average bankfull channel width category
Average bankfull channel width (m)
Average bankfull channel depth category
Average bankfull channel depth (m)
Mean discharge category
Mean annual discharge (m3/s)
Average channel gradient category
Average channel gradient
Average unit stream power (W/m2)


Project background

Reach length directly affected (m)
Project started 2013/05/05
Works started
Works completed
Project completed 2013/10/31
Total cost category
Total cost (k€) 160
160 k€
160,000 €
Benefit to cost ratio
Funding sources

Cost for project phases

Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname
Investigation and design
Stakeholder engagement and communication
Works and works supervision
Post-project management and maintenance
Monitoring



Reasons for river restoration

Mitigation of a pressure Loss of suitable habitat and biodiversity due to human impacts ( stability improvements)
Hydromorphology
Biology Fish, Invertebrates
Physico-chemical
Other reasons for the project


Measures

Structural measures
Bank/bed modifications Bank improvement, Introduction of gravel, Adding sinuosity, Bank stabilisation
Floodplain / River corridor
Planform / Channel pattern
Other
Non-structural measures
Management interventions
Social measures (incl. engagement)
Other


Monitoring

Hydromorphological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Biological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Invertebrates No Yes No No No

Physico-chemical quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Any other monitoring, e.g. social, economic

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative


Monitoring documents



Additional documents and videos


Additional links and references

Link Description

Supplementary Information

Edit Supplementary Information